Three functional variants in the NLRP3 gene are associated with susceptibility and clinical characteristics of systemic lupus erythematosus.

OBJECTIVE: Nod-like receptor pyrin domain containing 3 (NLRP3) gene encodes an intracellular receptor whose dysregulation in systemic lupus erythematosus (SLE) has been reported in multiple studies. Activation of NLRP3 inflammasome leads to the induction of inflammatory response via cleaving and producing of specific cytokines. In the present study, we assessed the possible association between three functional polymorphisms in this gene and SLE risk in the Iranian population. These variants include two gain of function (rs4612666 and rs10754558) and one loss of function (rs6672995) which are correlated with modulation of expression of NLRP3. METHODS: A case-control study involving 110 SLE patients and 116 control subjects was undertaken to estimate the frequency of rs4612666, rs10754558, and rs6672995 genotypes using real-time PCR high resolution melting method (HRM). RESULTS: Our findings revealed significant associations between GG genotype and G allele of rs10754558 with increased risk of SLE (OR for GG genotype= 2.82; 95%CI [1.45-5.46]/OR for G allele= 1.97; 95%CI [1.36-2.87]). Although, no significant associations were recognized between allele and genotype frequencies of rs4612666 and rs6672995 polymorphisms with SLE risk (P > 0.05). Also, our analysis revealed that the C allele in rs4612666 and G allele in rs10754558 was correlated with the severity of disease activity (P < 0.001). Moreover, these common variants were associated with lower age of onset and some clinical symptoms in the patient group, such as skin manifestation, neurological symptom and, renal involvement (P < 0.05). CONCLUSION: This study demonstrates a substantial association between NLRP3 polymorphisms with increased risk, clinical symptoms, and the severity of disease activity of SLE.

Association of Three Functional Polymorphisms in the NLRP3 Gene with Susceptibility to Rheumatoid Arthritis in the Iranian Population.

BACKGROUND: Rheumatoid arthritis (RA) is a complex systemic autoimmune disorder with multifactorial nature. Numerous previous studies have shown that several genes are involved in the pathogenesis and increased risk of RA. The Nod-like receptor pyrin domain containing 3 (NLRP3) is involved in the regulation of innate immunity and its upregulation has previously been reported in RA. OBJECTIVE: To evaluate the correlation between 3 functional polymorphisms of NLRP3 and its gene expression and RA risk. METHOD: One hundred and fourteen patients with RA and 120 healthy participants were recruited to this case-control study. Genotyping of rs4612666 (intronic variant), rs10754558 (3UTR variant), and rs6672995 (downstream variant) were performed applying the real­time polymerase chain reaction high­resolution melting (HRM) method. RESULTS: Based on logistic regression analysis, subjects with CC genotype and C allele in rs4612666 had increased risk of RA (OR for CC genotype= 3.10; 95%CI [1.78-8.26]/ OR for C allele= 2.00; 95%CI [1.45-3.10]). Furthermore, in the patient groups, there was a significant relationship between the concentration of C-reactive protein (CRP) and rs4612666 and rs10754558 polymorphism (p < 0.05). Besides, our results revealed no significant association between the genotype and allele frequency of rs10754558 and rs6672995 and the risk of RA (P> 0.05). CONCLUSION: Our findings propose a significant association between rs4612666 polymorphism and increased risk of RA in the Iranian population. Moreover, rs4612666 and rs10754558 were correlated with disease activity.

Investigation of rs531564 Polymorphism in the Primary MicroRNA-124 Gene in Patients with Systemic Lupus Erythematosus and Rheumatoid Arthritis: Association with Disease Susceptibility and Clinical Characteristics.

MicroRNA-124 (miR-124) is known as an important regulator of the immune system and inflammatory response. Studies have reported that this miRNA is dysregulated in autoimmune disorders such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). A functional analysis demonstrated that rs531564 (C>G) affects the biogenesis of primary microRNA transcript-124 (pri-miR-124) and changes the expression of mature miR-124. In the present study, for the first time, we intended to evaluate the possible association between rs531564 polymorphism with SLE and RA risk.  In this case-control study, 110 patients with SLE, 115 patients with RA, and 120 healthy subjects were enrolled to evaluate rs531564 genotypes with real-time polymerase chain reaction (PCR) high resolution melting method. Our findings demonstrated that frequency of GC genotype and G allele were considerably higher in the control group than RA patients, demonstrating that that GC genotype and G allele have a protective effect for healthy individuals (GC vs CC; OR: 0.29; 95%CI [0.12,0.67] and G vs C; OR: 0.42; 95%CI [0.23,0.78]). However, no significant correlation was confirmed between allele and genotype frequencies of rs531564 with SLE risk (p>0.05). However, the G allele in rs531564 polymorphism was associated with serum level of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), anti-dsDNA antibody, C3, C4, and creatinine, and frequency of renal involvements in SLE patients (p<0.05). Moreover, in RA patients, the G was correlated with lower concentration ESR and CRP (p<0.001).  Our findings propose a considerable association between rs531564 polymorphism in the pri-miR-124 gene with susceptibility and clinical characteristics of RA and SLE in the Iranian population.

Strong association of common variants in the miRNA-binding site of NOD2 gene with clinicopathological characteristics and disease activity of systemic lupus erythematosus.

INTRODUCTION/OBJECTIVES: Systemic lupus erythematosus (SLE) is a multifactorial systemic autoimmune disease, in which genetic susceptibility plays a pivotal role. The nucleotide oligomerization domain 2 (NOD2) gene is one of the main regulators of chronic inflammatory conditions and could be involved in SLE pathogenesis. Single nucleotide polymorphisms (SNPs) in miRNA binding sites which are located in 3'UTR of the NOD2 gene could be associated with SLE risk by dysregulation of NOD2 expression. In the present study, we assessed the possible association between SNPs rs3135500 and rs3135499 in the NOD2 gene with SLE risk in the Iranian population. METHODS: A case-control study using 110 SLE patients and 120 control subjects was undertaken to estimate rs3135500 (G > A) and rs3135499 (A > C) genotypes via real-time PCR high-resolution melting method (HRM). RESULTS: No significant association was observed between allele and genotype frequencies of rs3135500 and rs3135499 polymorphisms and SLE risk in this population (P > 0.05). However, there was an obvious association between rs3135500 (A allele) with laboratory factors that are associated with disease activity (P < 0.05) and some clinical manifestations that are associated with disease severity such as neurological symptoms, skin manifestations, renal involvements, and higher serum concentration of creatinine (P < 0.05). Besides, rs3135499 (C allele) was correlated with renal involvement and also the concentration of creatinine (P < 0.05). Moreover, in the patients group, the risk alleles in these polymorphisms were associated with lower age of onset (P < 0.05). CONCLUSIONS: Our results suggest a substantial association between NOD2 polymorphisms with clinicopathological characteristics and SLE disease activity. Key Points • Single nucleotide polymorphisms (SNPs) in miRNA binding sites which are located in 3'UTR of the NOD2 gene could be associated with SLE risk by dysregulation of NOD2 expression. • Our results suggested that two miRSNPs (rs3135500 and rs3135499) in the NOD2 gene were meaningfully correlated with clinicopathological characteristics and disease activity of SLE.